Weight-for-length for girls at 49 cm

At a length of 49 cm, the median weight for girls on the WHO Child Growth Standards is 3.16 kg (6 lb 15 oz): half of girls of this length weigh less and half more. The middle half of girls, from the 25th to the 75th percentile, falls between 2.97 and 3.36 kg, a spread of 0.39 kg. The outer lines of the chart, the 2nd and 98th percentiles, sit at 2.65 and 3.81 kg.

At 47 cm the median weight is 2.80 kg, so 2 cm of extra length goes with about 0.36 kg more weight at the median. At 51 cm it is 3.56 kg. 49 cm is close to the median length of girls at birth (49.1 cm). Weight-for-length compares a child's weight with other children of the same length, whatever their age, which is why it can read differently from weight-for-age for a long or a short baby.

For boys at a length of 49 cm the median is 3.13 kg, 0.03 kg less than for girls, which is why the charts are drawn separately by sex.

On the older CDC 2000 weight-for-length charts, which some clinics and websites still use before age 2, the median at a length of 49 cm is 3.15 kg. A girl exactly on the WHO median would read as about the 51st percentile there, one reason two charts can give different answers for the same weight.

Reading the table: a girl at a length of 49 cm who weighs 3.30 kg is at about the 69th percentile, meaning that out of 100 girls of that length, about 69 weigh less.